Drive plate for automotive vehicle

ABSTRACT

A drive plate (E) for an automotive vehicle for transmitting a torque from a crankshaft (6) to a torque converter (7), while absorbing a thrust load applied from the torque converter to the crankshaft is formed with: a central mount portion (11) for mounting a crankshaft; an outer gear (20) formed in an outermost circumference of the drive plate; a plurality of weight reducing holes (30) formed between the central mount portion and the outer gear at regular angular intervals; and a plurality of the outer mount portions (12) for mounting a torque converter (7) formed near an outer circumference of the drive plate at regular angular intervals. In particular, the outer mount portions (12) are formed in such a way as to project radially inward from the outer gear (20) into the weight reducing holes (30), respectively. Since the virtual bending radius (deformation length L) of the drive plate can be increased, the bending angle (DA1) can be reduced when a thrust load is applied from the torque converter to the drive plate, so that it is possible to reduce a bending stress concentrated at the central mount portion (11) as small as possible, for prevention of the drive plate from being damaged.

This is a continuation of application Ser. No. 08/535,555 filed Sep. 28,1995, now abandoned.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a drive plate for an automotivevehicle, and more specifically to a drive plate for linking an enginecrankshaft with a torque converter of an automatic transmission. Here,the drive plate implies a plate disposed midway in a transmission routefrom an engine to vehicle wheels in an automotive vehicle.

2. Description of the Related Art

FIGS. 1A, 1B and 1C show an example of a prior art drive plate 1 for anautomotive vehicle. The drive plate 1 is composed of a body portion 2formed by pressing a metal plate and a ring gear 3 fixed integral withthe outer circumference of the body portion 2 by welding. Further, thebody portion 2 is formed with a central mount portion 4 fixed to acrankshaft 6 and an outer circumferential mount portion fixed to atorque converter 7, as depicted in FIG. 1B. Further, as shown in FIG.1A, a plurality (e.g., eight) of crankshaft mounting holes 4a are formedin the central mount portion 4 at regular angular intervals along aconcentric circle, and a plurality (e.g., four) of torque convertermounting holes 5 are also formed in the outer circumferential mountportion at regular angular intervals along another concentric circle. Inaddition, the central mount portion 4 and the outer circumferentialmount portion are dislocated in an axial direction of the drive plate 1by deforming an intermediate portion A (See FIG. 1A) between the two bya drawing processing. Further, in FIG. 1A, 2a denotes an innermost holethrough which the crank shaft is passed, and 2b denotes additional holesformed to reduce the weight of the drive plate 1.

In assembly of the vehicle drive plate 1, an end portion 6a of thecrankshaft 6 (See FIG. 1B) is fixed to the drive plate 1 with aplurality of mount bolts 6b fitted into the crank mount holes 4a; and aboss portion 7a of the torque converter 7 is fixed to the drive plate 1with a plurality of mount bolts 7b fitted into the converter mount holes5. After assembly, therefore, it is possible to transmit the torque ofthe crankshaft 6 to the torque converter 7 and further to absorb athrust load of the torque converter 7.

In the above-mentioned prior art drive plate 1, however, whenever athrust load is applied from the torque converter 7 to the drive plate 1,since being formed by a drawing press, the intermediate area A is easilybent. On the other hand, since being formed rigid, the outer area B (SeeFIG. 1A) is hardly deformed. Consequently, when a thrust load is appliedto the drive plate 1, only the intermediate portion A is deformed, andthe outer area B is not deformed, as shown by phantom lines shown inFIG. 1C. In other words, since the virtual bending radius (i.e., adeformation distance) L of the drive plate 1 is small, the intermediatearea A is deformed at a relatively large deflection angle DA. Underthese conditions, although the above-mentioned deformation can absorbthe thrust load applied from the torque converter 7 to the drive plate1, when this deflection angle DA increases beyond a predetermined limit,since a bending stress generated in the vicinity of the central mountportion 6 is concentrated excessively, there exists a problem in thatthe bending stress exceeds an allowable stress limit, with the resultthat the central mount portion 4 of the crankshaft 6 is damaged orbroken.

SUMMARY OF THE INVENTION

With these problems in mind, therefore, it is the object of the presentinvention to provide a drive plate for an automotive vehicle, which canreduce the bending stress generated when a thrust load is applied fromthe torque converter to the drive plate, that is, in the axial (thrustforce application) direction of the drive plate, as effectively aspossible.

To achieve the above-mentioned object, the present invention provides adrive plate for an automotive vehicle for transmitting a torque from acrankshaft to a torque converter, while absorbing a thrust load appliedfrom the torque converter to the crankshaft, formed with: a centralmount portion (11) for mounting a crankshaft; an outer gear (20) formedin an outermost circumference of the drive plate; a plurality of weightreducing holes (30) formed between said central mount portion and saidouter gear at regular angular intervals; and a plurality of the outermount portions (12) for mounting a torque converter (7) formed near anouter circumference of the drive plate at regular angular intervals insuch a way as to project radially inward from the outer gear (20) intosaid weight reducing holes (30), respectively.

Further, it is preferable that said outer gear (20) is formed bydirectly engraving teeth in an outer annular portion formedsimultaneously when a body portion (10) of the drive plate is formed.

Here, said weight reducing holes (30) are each formed into a sectorialshape having outer and inner arc portions (30c, 30c), and each of saidouter mount portion (12) projects radially inward into each of thesectorial weight reducing hole (30) at a middle of the outer arc portion(30b) thereof. Further, the outer mount portions (12) and said weightreducing holes (30) of the same number are arranged radiallysymmetrically with respect to the center of the drive plate one-to-onecorresponding relationship with respect to each other.

Further, it is preferable that the drive plate is further formed with aplurality of circular through holes (31) arranged between said twosectorial weight reducing holes (30). Further, it is preferable that theinner arc portions (30c) of the sectorial weight reducing holes (30) areformed in close proximity to said central mount portion 11 and furtherthe outer arc portions (30b) of the sectorial weight reducing holes (30)are formed in close proximity to said outer gear (20).

In the drive plate according to the present invention, since thedeformation distance L1 (the virtual bending radius) can be increased byforming the converter mounting holes as radially outward as possible bybest use of the weight reducing holes, when the converter mountingportion of the driver plate is deformed toward the crankshaft in theaxial (thrust) direction thereof, it is possible to reduce thedeflection angle as small as possible, so that the bending stress so farconcentrated at the central mount hole for mounting the crankshaft canbe reduced markedly, thus preventing the central mount portion of thedrive plate from being damaged.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a front view showing a prior art drive plate for anautomotive vehicle;

FIG. 1B is a cross-sectional view taken along the line IB--IB in FIG.1A;

FIG. 1C is an illustration for assistance in explaining the deformationof the prior art drive plate;

FIG. 2A is a front view showing a first embodiment of the drive platefor an automotive vehicle according to the present invention;

FIG. 2B is a cross-sectional view taken along the line IIB--IIB in FIG.2A;

FIG. 2C is an illustration for assistance in explaining the deformationof the drive plate shown in FIGS. 2A and 2B;

FIG. 3A is a front view showing a second embodiment of the drive platefor an automotive vehicle according to the present invention;

FIG. 3B is a cross-sectional view taken along the line IIIB--IIIB inFIG. 3A;

FIG. 4A is a front view showing a modification of the second embodimentof the drive plate for an automotive vehicle according to the presentinvention;

FIG. 4B is a cross-sectional view taken along the line IVB--IVB in FIG.4A;

FIG. 5A is a front view showing a third embodiment of the drive platefor an automotive vehicle according to the present invention;

FIG. 5B is a cross-sectional view taken along the line VB--VB in FIG.5A;

FIG. 6A is a front view showing a modification of the third embodimentof the drive plate for an automotive vehicle according to the presentinvention; and

FIG. 6B is a cross-sectional view taken along the line VIB--VIB in FIG.6A.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Embodiments of the drive plate according to the present invention willbe described hereinbelow with reference to the attached drawings.

First embodiment of the drive plate E is shown in FIGS. 2A, 2B and 2C.

As shown in FIGS. 2A and 2B, a drive plate E is composed of a centralmount portion 11 fixed to a crankshaft 6 and an outer circumferentialmount portion 12 fixed to a torque converter 7. Further, an outer gear20 is formed on the outermost circumferential surface of the drive plateE. In addition, a plurality (e.g., four) of weight reducing holes 30 areformed in the intermediate portion (between the central mount portion 11and the outer mount portion 12) of the drive plate E at regular angularintervals. Therefore, the drive plate E can transmit a torque of thecrankshaft 6 to the torque converter 7, and further can absorb thethrust load applied from the torque converter 7 to the drive plate E.

The feature of this first embodiment is that a plurality (e.g., four) ofouter mount portions 12 for mounting a torque converter 7 are formedalong an outer circumference of the drive plate E at regular angularintervals in such a way that each of the outer mount portions 12projects radially inward from the outer gear 20 to each of the weightreducing holes 30 (as shown in FIG. 2A), which is different from theprior art drive plate E formed with an intermediate portion A drawn ordeformed by a drawing press (as shown in FIG. 1A).

In more detail, the drive plate E shown in FIG. 2A is composed of a bodyportion 10 formed by pressing (plastic processing) a metallic plate andan outer gear 20 formed in the outer circumference of the body portion10. Further, the body portion 10 is formed with a central mount portion11 fixed to a crankshaft 6 and a plurality of outer mount portions 12fixed to a torque converter 7, as shown in FIG. 2B.

Further, as shown in FIG. 2A, a plurality (e.g., eight) of crankshaftmounting holes 11a are formed in the central mount portion 11 at regularangular intervals along a concentric circle.

Further, a plurality (e.g., four) of outer mount portions 12 for atorque converter 7 are formed along an outer circumference of the driveplate E at regular angular intervals in such a way that each of theouter mount portions 12 projects radially inward from the outer gear 20to each of the weight reducing holes 30, as shown by meshed(cross-hatched) portion in FIG. 2A. Further, one torque convertermounting hole 12a is formed in each outer mount portion 12.

Further, in FIG. 2A, a through hole 11b is formed at the center of thecentral mount portion 11 for mounting the crankshaft 6.

The weight reducing holes 30 are each formed into a sectorial (fan)shape in such a way as to be symmetrical right and left and up and downwith respect to a diameter line passing through the center of thecentral mount portion 11 and the center of each of the convertermounting holes 12a. Further, each weight reducing hole 30 is formed witha radially outermost arc portion 30a arranged on a concentric circlepassing through the center of the converter mounting hole 12a and with amiddle radially concave portion 30b so as to form an inner part of eachouter mount hole 12 for mounting the torque converter 7. Further, eachinnermost arc portion 30c of each weight reducing hole 30 is arranged ona concentric circle of the central mount portion 11 for mounting thecrankshaft 6 in the vicinity of the central mount portion 11.

In the same way as with the case of the prior art drive plate E, inassembly of the vehicle drive plate E, as shown in FIG. 2B, an endportion 6a of the crankshaft 6 is fixed to the drive plate E with aplurality of mount bolts 6b fitted into the crank mount holes 11a; and aboss portion 7a of the torque converter 7 is fixed to the drive plate Ewith a plurality of mount bolts 7b fitted into the converter mount holes12a. After assembly, therefore, it is possible to transmit a torque ofthe crankshaft 6 to the torque converter 7 and further to absorb athrust load of the torque converter 7 applied from the torque converter7 to the drive plate E.

In the drive plate E as described above, when a thrust load is appliedfrom the torque converter 7, since the outer mount portion 12 formounting the torque converter 7 are formed in the vicinity of the weightreducing holes 30 and by best use of the presence of the weight reducingholes 30, respectively, the thrust load is applied to the concentriccircle portion along the outermost arc portion 30a of the weightreducing holes 30, so that the drive plate E is deformed as shown byphantom lines shown in FIG. 2C. As a result, it is possible to increasethe virtual bending radius (deformation distance) L1 markedly, ascompared with the deformation distance L (shown in FIG. 1C) of the priorart drive plate E. In addition, since the outer portion of the driveplate E for mounting the torque converter 7 can be deformed (not rigidas with the case of the prior art), it is possible to prevent a bendingstress from being concentrated only at the central mount portion 11 formounting the crankshaft 6. As a result, the deflection angle DA1 can bereduced smaller than that DA shown in FIG. 1C, so that the bendingstress generated in the vicinity of the central mount portion 11 formounting the crankshaft 6 can be reduced, and thereby the drive plate Ecan be prevented from being damaged or broken.

FIGS. 3A and 3B show a second embodiment of the drive plate E for anautomotive vehicle according to the present invention. In thisembodiment, the outermost arc portion 30a of the weight reducing holes30 are located outward from a concentric circle passing through theconverter mounting holes 12a to the outer gear (20) side, so that it ispossible to further lengthen the deformation distance L1 and thereby toreduce the deflection angle DA1. As a result, the bending stressconcentrated at the drive plate E can be further reduced.

FIGS. 4A and 4B show a modification of the second embodiment, in which aplurality (e.g., four) through holes 31 are additionally formed betweentwo adjacent weight reducing holes 30, respectively. In thismodification, since the bending stress concentrated at the centralportion of the drive plate E can be further decentralized, it ispossible to further reduce the bending stress generated at the driveplate E.

FIGS. 5A and 5B show a third embodiment of the drive plate E for anautomotive vehicle according to the present invention. In thisembodiment, the sectorial angle of each weight reducing hole 30 isformed wider along the circumferential direction, so that it is possibleto further reduce the bending stress concentrated at the central portionof the drive plate E.

Further, in the respective embodiments described above, the outerannular gear 20 formed with gear teeth in the outer circumferencethereof is first prepared. After that, the outer annular gear 20 isfixed integral with the outer circumferential of the body portion 10 bywelding.

FIGS. 6A and 6B show a modification of the third embodiment, in whicheach innermost arc portion 30c of each weight reducing hole 30 is formedin close proximity to the central mount portion 11 for mounting thecrankshaft. In this modification, since the bending stress generated atthe central portion of the drive plate E can be further decentralized,it is possible to further reduce the bending stress concentrated at thedrive plate E.

Further, in this modification, being different from the otherembodiments, the body potion 10 and an outer annular portion which isexpected to be the outer gear 20 are formed simultaneously at first.After that, the teeth of the outer gear 20 are formed in the outercircumference of the formed outer annular portion.

Further, in FIGS. 2A, 3A, 4A, 5A and 6A, the meshed (cross-hatchedportions) are shown only for emphasis, so that the meshed portion 12 isflush with the adjoining portion, as shown in FIGS. 2B, 3B, 4B, 5B and6B, respectively.

As described above, in the vehicle drive plate according to the presentinvention, since the deformation distance L1 can be increased by formingthe converter mounting holes as radially outward as possible by best useof the weight reducing holes, when the converter mounting portion of thedriver plate is deformed toward the crankshaft in the axial (thrust)direction thereof, it is possible to reduce the deflection angle assmall as possible, so that the bending stress so far concentrated at thecentral mount hole for mounting the crankshaft can be reduced markedly,thus preventing the central mount portion of the drive plate from beingdamaged.

What is claimed is:
 1. A drive plate for an automotive vehicle fortransmitting a torque from a crankshaft to a torque converter to whichthe drive plate is attached, while absorbing a thrust load applied fromthe torque converter to the crankshaft, said drive plate comprising:adrive plate body having a central plate portion for mounting thecrankshaft, and an outer plate portion surrounding the central plateportion; an outer gear formed on an outer periphery of the drive platebody; a plurality of outer mounting portions associated with the outerplate portion with each mounting portion including an element formounting the torque converter, said plurality of outer mounting portionsbeing arranged in said outer plate portion at locations near the outerperiphery of the drive plate body at regular intervals in acircumferential direction of the drive plate body; a plurality of weightreducing holes formed in the outer plate portion at regular intervals ina circumferential direction of the outer plate portions; the outermounting portions corresponding in number to the weight reducing holesso that each and every weight reducing hole faces a corresponding one ofthe outer mounting portions, each said weight reducing hole having asectorial shape having outer and inner arc portions; said outer mountingportions and said weight reducing holes arranged radially symmetricallywith respect to the center of the drive plate body without encounteringany other hole in the outer plate portion; said inner arc portion ofeach of the weight reducing holes being in close proximity to saidcentral plate portion; and each outer mounting portion projecting in aradial direction from the outer gear into a corresponding weightreducing hole at a middle of a corresponding one of the outer arcportions of the weight reducing holes, so that the outer plate portionundergoes angular deflection relative to the central plate portion inresponse to a thrust load applied to the drive plate, thereby increasingthe radius of bending deflection at the outer mounting portions and thusreducing the angle of deflection so as to reduce the bending stressconcentrated at the central plate portion of the drive plate by thethrust load.
 2. The drive plate of claim 1, wherein said outer gear isformed by directly engraving teeth in the outer periphery of said driveplate body simultaneously when said drive plate body is formed.
 3. Thedrive plate of claim 1, wherein a width of each said weight reducinghole in a circumferential direction is wider than a width of each saidweight reducing hole in a radial direction.